• Journal of Korean Society of Transportation
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• v.25 no.3
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• pp.87-97
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• 2007

This paper proposes drivers' rational belief formation under a bounded traffic environment. This is to escape the criticism that excessive rationality (e.g., a driver's calculating ability and memory capacity) is required of drivers. Under bounded traffic environments. drivers do not have structural knowledge of traffic conditions and others' decisions. Simulations are carried out using a program coded in C. Consequently, the author found the learning process of drivers and the value of information can be differentiated by route conditions and the characteristics of driver groups. Also, it was found that rational drivers form different beliefs about traffic conditions even though they have the same traffic environment in a bounded traffic environment.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.12
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• pp.38-45
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• 2003

Recently, localized QoS routing scheme was recently proposed for overcome drawbacks of global state QoS routing schemes. Localized QoS routing dose not exchange QoS states among routers, but use virtual capacity based routing scheme instead. In localized QoS routing, to archive good performance, a set of candidate paths must be selected between the source and the destination effectively. In this paper we propose a few heuristics for effective path selection and develop path selection algorithms based on the heuristics. More detail analysis of the proposed algorithm is presented with simulation results which demonstrate that the path selection method can very affect the performance of localized QoS routing.

• Journal of Korea Society of Industrial Information Systems
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• v.20 no.5
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• pp.53-60
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• 2015

In this paper, the DCT based lossless image compression system which selects a limited number of DCT coefficients is proposed for the Lenna, Camerman, and Baboon image. The number of DCT coefficients to obtain a suitable image quality for the reconstructed image is computed by simulation. The image size of $256{\times}256$ are used in the experiment. The PSNR values for the reconstructed image by selecting limited number of DCT coefficients are found. It is shown that the minimun number of the coefficients for Lenna, Cameramen Baby and Babbo image to obtain PSNR=30 are N=16, 32, 37, 55, respectively. The result can provide the guideline of the importance of the DCT coefficient toward the compression for the tested image of the Lena, Cameraman, and Baboon.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.5
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• pp.71-76
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• 2013

This paper considers an approach of secondary user selection method in cooperative spectrum sensing, which two users with the best SNR in sensing channel and in reporting channel, respectively, are selected to cooperate with each other in the spectrum sensing. The sensing results reported by two users are then combined to detect PU signal operation. A comparison between this proposed method with conventional selection technique in which only the user having the best sensing channel SNR is selected shows that the proposed method outperforms. We make an assumption that sensing channels experience identical, independent distributed (i.i.d) Rayleigh fading and the reporting channels are invariant and non-identical. Simulation results are derived for demonstration.

• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.5
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• pp.661-666
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• 2009

Modular snake-like robots, which consist of series of modules, are robust for failure and have flexible locomotions for environment. However, they are difficult to control and few efficient and various locomotions are introduced yet. In this paper, GA based phase generation and trajectory generation approaches are implemented and compared for locomotion of snake-like robots and extended for analysis for selections of partial modules. In addition, modeling and simulation environments are implemented in Webots simulator and above GA based experiments for locomotion are executed for KMC snake-like robot.

• Journal of Broadcast Engineering
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• v.24 no.4
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• pp.613-622
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• 2019

A differential codebook design method using wireless channel's temporal correlation is proposed over closed loop multiple-input single-output (MISO) system. The single layer codewords in a codebook are selected among a set of phase elements. In the conventional codeword selection rule, codewords are assumed to be on a spherical cap and sine formula was used. In this paper, however, a new method using Pythagoras formula is employed to simplify computational complexity. Also, an adaptive differential codebook selection is adopted to enhance performance. Monte-Carlo simulations demonstrate that the proposed codebook is superior to the conventional ones.

• Journal of Internet Computing and Services
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• v.23 no.5
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• pp.9-15
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• 2022

This paper proposes a coordinated multi-point communication (CoMP) method with channel selection to improve performance of a macro user equipment (MUE) in a dense small-cell network environment in a building located within coverage of a macro base station (MBS). In the proposed CoMP method, in order to improve the performance of the MUE located in the building, A small-cell base station (SBS) selects a channel with lower interference to the neighboring MUE and transmits appropriate signals to the MUE requiring CoMP. Simulation results show that the proposed CoMP method improves the performance of the MUE by up to 164% and 51%, respectivley, compared to a random channel allocation based traditional SBS network and CoMP method.

• Journal of the Korea Society for Simulation
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• v.16 no.4
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• pp.13-22
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• 2007

Fault detection of cycle-based signals is typically performed using statistical approaches. Univariate SPC using few representative statistics and multivariate analysis methods such as PCA and PLS are the most popular methods for analyzing cycle-based signals. However, such approaches are limited when dealing with information-rich cycle-based signals. In this paper, process fault defection method based on wavelet analysis is proposed. Using Haar wavelet, coefficients that well reflect the process condition are selected. Next, Hotelling's $T^2$ chart using selected coefficients is constructed for assessment of process condition. To enhance the overall efficiency of fault detection, the following two steps are suggested, i.e. denoising method based on wavelet transform and coefficient selection methods using variance difference. For performance evaluation, various types of abnormal process conditions are simulated and the proposed algorithm is compared with other methodologies.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.5
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• pp.985-993
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• 2001

Neural networks are shown to be effective in being able to distinguish incomplete penetration-like weld defects by directly analyzing the plasma which is generated on each impingement of the laser on the materials. The performance is similar to that of existing methods based on extracted feature parameters. In each case around 93% of the defects in a database derived from 100 artificially produced defects of known types can be placed into one of two classes: incomplete penetration and bubbling. The present method based on classification using plasma is faster, and the speed is sufficient to allow on-line classification during data collection.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2017.11a
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• pp.74-75
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• 2017

The operations of the warehouses are labor intensive. Automation of the warehouse is made by efforts to shorten the work time and reduce the cost according to the change of the production form of the company and the buyer's demand. Storage warehouses vary in size and shape, and equipment and facilities used in storage warehouses vary according to purpose and use. In order to automate storage, it is necessary to introduce an operating system, which varies depending on the type of equipment and operation policy. In this paper, we review the requirements for the automation of small and medium-sized storage warehouses, and classify the equipment selection and operating system options into effective scenarios to introduce an effective automation system. Therefore, simulation is performed for each scenario, and the effect of automation is examined, and the effect of automation is verified through economic analysis through cost for automation introduction.